There has been proposed a light emitting diode (LED) power supply device that can adjust the brightness and the color temperature of light emitted from an LED module (JP 2012-226924 A, hereinafter referred to as Document 1). The LED power supply device of Document 1 includes the LED module and a power supply device. The LED module includes a first light emitting unit for emitting first color light and a second light emitting unit for emitting second color light. The power supply device supplies an electric current to cause the LED module to emit light. The power supply device includes a constant current output circuit, a color temperature control circuit, and a control circuit. The control circuit receives a light output control signal and a color temperature signal from an external dimmer. The light output control signal is a pulse width modulation (PWM) signal, and indicates a desired brightness by the duty cycle. The color temperature signal is a PWM signal, and indicates a desired color temperature by the duty cycle. The control circuit adjusts the brightness (light output) of the LED module by controlling the current outputted from the constant current output circuit based on the light output control signal. Also, the control circuit adjusts the color temperature of light emitted from the LED module by controlling a blinking cycle of the first light emitting unit and a blinking cycle of the second light emitting unit based on the color temperature signal.
The LED power supply device disclosed in Document 1 can receive and handle the light output control signal represented by the PWM signal indicating a desired brightness by the duty cycle. However, the LED power supply device of Document 1 cannot handle the light output control signal represented by a signal other than the PWM signal. That is, the LED power supply device of Document 1 cannot cooperate with a dimmer that outputs a light output control signal represented by a signal other than the PWM signal.